Can my employer decrease benefits/wages to one employee while keeping the same benefits/wages to others?

I work for a large corporation. When I was hired, my compensation package included a base salary, a company car, cell phone, laptop and the usual medical/insurance package. Today they announced that they are discontinuing the company car for employees that do not drive over a certain amount of mileage per year. The company car benefit is taxed just like wages, if I use the car for 100% personal use, I am taxed an additional $6000/year in wages. Due to my geographical location, i fly more than I can drive and as a result I will probably lose my car. The company is not making any yearly compensation to those that are losing the car, it is just gone. I have no control over where I travel each week.